When irrigating extensive areas of land, long sprinkler lines have been used for some time. Water has been supplied to these lines from buried pipes called main lines with spaced risers projecting above the surface of the ground for connection to the sprinkler lines. Each time a sprinkler line had to be moved, manual labor was required for this purpose. This was a laborious and time consuming operation. As time went on, the sprinkler lines, which can reach a length of a quarter of a mile and more were fitted with wheels to make them easier to move. Eventually, power was supplied in one way or another to the wheeled lines to keep them moving slowly along the desired path parallel to the direction of the main line with flexible hoses extending between the water inlet end of the spinkler lines and the riser to which the sprinkler line was connected. Since the main line can be eight or more inches in diameter with the water pressure in the main line high, the required size and strength of the flexible hoses became extremely burdensom in manual operation. Proposals were therefore made to facilitate connection of the sprinkling lines to successive risers with the least manual effort. Three examples of such proposals are illustrated in Engel U.S. Pat. No. 2,740,228, Stafford U.S. Pat. No. Re. 26,285 and Smith et al. U.S. Pat. Nos. 3,381,893 and 3,446,434. Such proposals provided for intermittent connection of the sprinkler line to the main line utilizing power assisted mechanical devices as the hoses or telescoping pipes were moved from riser to riser, with the sprinkler line continuing to move along at the desired constant rate.
In order to provide for a continual source of water to the sprinkler line Rogers U.S. Pat. No. 3,463,175 and Standal U.S. Pat. No. 4,036,436 proposed systems in which one riser is always connected to the sprinkler line, this being accomplished by having pipe or hose connections to the sprinkler line connect with devices which span three risers. By this arrangement, the forward part of the device is disconnected from one riser and goes on to a second riser ahead of the first riser and on connection of the device with the second riser, the hindmost part of the device, which has been connected to a third riser which is behind the first riser in the main line, moves up to connect with the first riser. As far as known to the applicant, these proposals were never put into use. In addition to requiring closely spaced risers, the mechanical problems associated with these systems appear to have ruled out their use.
Von Linsowe U.S. Pat. No. 3,729,016 discloses another form of system for continuously feeding the water to a sprinkler line, but this system requires twin main lines since the twin coupling devices for connecting the sprinkler line to the main line cannot pass each other. This proposal appears to have the same history in practice as the Rogers and Standal systems.
In the system of the present invention, the faults and disadvantages of the prior systems have been eliminated by the provision of a plurality of rigid pipes or water carrying arms arranged for successive coupling with novel valves in succeeding risers on a main line by virtue of these arms having their water outlets connected to a rotatable water manifold carried along the length of the water main by a conveyance, the water outlet of the rotatable water manifold, being connected to the water inlet end of the sprinkler line through a swivel joint conduit. The conveyance carries the apparatus along and since a single water carrying arm is connected to a single riser at any one time, movement of the conveyance causes or assists the pipes and water manifold to rotate and thereby bring the arms successively into coupling relationship with successive risers along the main line. Thus, continuous water flow is achieved between the water main line and the sprinkler line without the mechanical and functional difficulties of prior systems.